Description of the FAA's Local Area Augmentation System (LAAS)*

The Local Area Augmentation System (LAAS) is the Federal Aviation Administration's ground-based augmentation system (GBAS) for local area differential GPS (DGPS). It will support all categories of precision approach. LAAS is currently under advanced development and specification. The purpose of this paper is to provide a system description of LAAS and to describe important related developments for the aviation and navigation communities. Both top-level and intermediate-level descriptions are given, with emphasis on the Ground Segment. Three distinguishing advances are described in more detail: Multipath Limiting Antenna, Airport Pseudolite, and a method for transforming integrity parameters from the pseudorange to the position domain.